Chip with simple program for Toy

[w_tom]

Effective protection is not possible by unplugging. First,
you are not available even one third of the day. Most of the
time is spent sleeping or out working, etc. Second, many of
those appliances cannot be always unplugged - ie answering
machine, phone, and that TV. Having spent many decades
learning this stuff, I now have equipment on during
thunderstorms - often following the storm in real time. No
damage because money was not wasted on grossly overpriced
protectors recommended by urban myth purveyors. Provided is
both the superior protection method AND the less expensive
method. It is called 'whole house' protector. So effective
that the phone company installs one for free in your phone
line premise interface.

Wires most often struck are wires highest on the pole. These
wires make a direct connection to every household appliance
without any earthed 'whole house' protector. Earthing the
direct strike is essential to protection. One minimally
acceptable 'whole house' protector is sold in Home Depot as
Intermatic IG1240RC. Many other responsible manufacturers
such as Leviton, Square D, Cutler Hammer, Erico, Polyphaser,
Furse, etc all sell these products. But still we have people
foolishly recommending plug-in protectors. When challenged,
we discover they have no basic electrical knowledge - which
explains why they did not even know the phone line protector
already exists. Then when those plug-in protectors fail, they
say nothing can protect from lightning - and recommend more of
those ineffective protectors.

One can never unplug for effective protection. The human is
not reliable enough nor available 24/7. But 'whole house'
protectors connected 'less than 10 feet' to earth ground are
that reliable.

Rich, you had to rearrange transistor leads because Japanese
use ECB configuration verses an American EBC configuration?

Rich Grise wrote:

An apartment I was living in once took a direct hit. It's pure dumb
luck that I had unplugged the modem - it took out the answering machine
and a desk phone. It also blew out a couple of exit lights - the
manager said there was a total of about $7,000 damage from that one
strike.

So, if it's actively lightninging, you're not being overly/unneccesarily
cautious to unplug stuff. It also took out the on/off transistor in
the TV, so the remote wouldn't turn it off any more. I had to get up
and walk to the TV, until I got it fixed, of course. I took it to
the shop, and asked how much a diagnosis was, which was about $35.00,
and the repair would have been about $85.00, so I just asked the tech
to mark the transistor so I could replace it myself. I had to rearrange
the leads on a plastic 2222, but it fixed it.

Cheers!
RIch

 

[Bert]

Thanks for your reply; I've send them my request.
I hope however that the prices for the chip will go a lot lower when you
talk about 10.000 chips.... because else I can stop designing right now

Grtz
Berrie


"Jamie" <jamie_5_not_valid_after_5_Please@charter.net> schreef in bericht
news:10llfvdtko7vb70@corp.supernews.com...

look at PIC chips.
www.microchip.com
they have very small 8 pin types that would be
more than enough for that.
you need a programmer from them to write the
code in it.. its not hard to do and its fun to
learn, after you see what can be done with these
programmable integrated chips you will wonder why
you never looked there before!


Berrie wrote:
Dear Reader,

I'm looking for information (quotation for production quantity's)
for a little chip in a toy.

The only thing that this chip has to do is pick a RANDOM number (10th of
a
second) between 1 and 24 seconds and then change the direction of a
motor.

eg; 1.4 seconds to the left
3.1 seconds to the right
12.4 seconds to the left
8.3 seconds to the right

etc...etc..

Any help in this matter would be greatly appreciated.

Thanks!

Berrie

 

[petrus bitbyter]

"Berrie" <berrie@xooby.com> schreef in bericht
news:b97ccce1.0409290352.5ca094ae@posting.google.com...

Dear Reader,

I'm looking for information (quotation for production quantity's)
for a little chip in a toy.

The only thing that this chip has to do is pick a RANDOM number (10th of a
second) between 1 and 24 seconds and then change the direction of a
motor.

eg; 1.4 seconds to the left
3.1 seconds to the right
12.4 seconds to the left
8.3 seconds to the right

etc...etc..

Any help in this matter would be greatly appreciated.

Thanks!

Berrie

Most simple thing I can imagine is an appropriate programmed eight pins PIC
or a similar tiny AVR. You wil need some transistors to drive the motor as
you will not find random generators with motor driving capabilities.

petrus bitbyter


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.754 / Virus Database: 504 - Release Date: 6-9-2004

 

[Jamie]

the small 8 pin chips are cheap.
but you may want to have some one bulk
program them for you.


Bert wrote:

Thanks for your reply; I've send them my request.
I hope however that the prices for the chip will go a lot lower when you
talk about 10.000 chips.... because else I can stop designing right now

Grtz
Berrie


"Jamie" <jamie_5_not_valid_after_5_Please@charter.net> schreef in bericht
news:10llfvdtko7vb70@corp.supernews.com...

look at PIC chips.
www.microchip.com
they have very small 8 pin types that would be
more than enough for that.
you need a programmer from them to write the
code in it.. its not hard to do and its fun to
learn, after you see what can be done with these
programmable integrated chips you will wonder why
you never looked there before!


Berrie wrote:

Dear Reader,

I'm looking for information (quotation for production quantity's)
for a little chip in a toy.

The only thing that this chip has to do is pick a RANDOM number (10th of

a

second) between 1 and 24 seconds and then change the direction of a
motor.

eg; 1.4 seconds to the left
3.1 seconds to the right
12.4 seconds to the left
8.3 seconds to the right

etc...etc..

Any help in this matter would be greatly appreciated.

Thanks!

Berrie

 

[John Fields]

On Wed, 29 Sep 2004 20:57:00 -0700, "john jardine"
<john@jjdesigns.fsnet.co.uk> wrote:

"RANDOM", Maybe easier said than done. A micro running a stored programme
can't do it just on it's own.
There's got to be available somewhere, a real random variable that the
micro can then use as a 'seed' to maybe generate series of psuedo-random
values.

---
For a toy, an 8 bit pseudo-random pattern is prob'ly good enough,
since you can get 255 tenth-second values out of the thing which you
load into an 8 bit down-counter, start the motor, and then count the
counter down with a 100ms clock. When the counter counts down to
zero, you send a clock to the pseudo-random sequence generator to
generate the next pattern, load it into the counter, reverse the
direction of the motor and run the counter down to zero again to start
the next timeout with the new value from the PRSG.

--
John Fields

 

[Bert]

Thanks all for your help:

this is what I foud as the cheapest out there.
(don't have high volume price yet)
--------------------------------

Program Memory Type Standard Flash
Program Memory Size (bytes) 384
RAM Size (bytes) 16
Data EEPROM Size (bytes) 0
I/O pins 4
Packages SOT-23, 8p DIP

Features
a.. 6-pin SOT-23 packaging

a.. Precision 4 MHz internal oscillator

a.. Baseline Core with 33 Instructions, 2 Stack Levels

a.. All single-cycle Instructions except for program branches which
are two cycles

a.. 12-bit wide instructions

a.. 8-bit wide data path

a.. 25 mA source/sink current I/O

a.. Low power (100nA) sleep current

a.. One 8-bit timer (TMR0)

a.. Watchdog timer (WDT)

a.. In Circuit Serial ProgrammingT (ICSPT) capability

a.. In-Circuit debugging support

a.. Programmable code protection
a..
--------------------------------------------------------------------

Please note that I don't have any electroninc knowledge... (but that
is hardly news i suppose
Why would I need 8 pins... what is so hard at getting a motor to
switch direction randomly



John Fields wrote:

For a toy, an 8 bit pseudo-random pattern is prob'ly good enough,
since you can get 255 tenth-second values out of the thing which you
load into an 8 bit down-counter, start the motor, and then count the
counter down with a 100ms clock. When the counter counts down to
zero, you send a clock to the pseudo-random sequence generator to
generate the next pattern, load it into the counter, reverse the
direction of the motor and run the counter down to zero again to start
the next timeout with the new value from the PRSG.

Would you be so kind and help me out a bit more.
Based on the info above I have a chip for less then 0,50 ct (still to much;
but ok... we're getting there)
Now how would you hook up a motor (what other parts are needed)...is there a
schematic example somewhere.
Where would I find motors (eg. lego/toy size...) I had hoped to keep this
whole
technical unit in the 1 to 2 dollar range...since it also need some plastic
parts too

Again; thanks for all the info you can give me.

Regards,

Berrie

 

[John Fields]

On Thu, 30 Sep 2004 12:46:47 +0200, "Bert" <b123s@hotmail.com> wrote:

Thanks all for your help:

this is what I foud as the cheapest out there.
(don't have high volume price yet)
--------------------------------

Program Memory Type Standard Flash
Program Memory Size (bytes) 384
RAM Size (bytes) 16
Data EEPROM Size (bytes) 0
I/O pins 4
Packages SOT-23, 8p DIP

Features
a.. 6-pin SOT-23 packaging

a.. Precision 4 MHz internal oscillator

a.. Baseline Core with 33 Instructions, 2 Stack Levels

a.. All single-cycle Instructions except for program branches which
are two cycles

a.. 12-bit wide instructions

a.. 8-bit wide data path

a.. 25 mA source/sink current I/O

a.. Low power (100nA) sleep current

a.. One 8-bit timer (TMR0)

a.. Watchdog timer (WDT)

a.. In Circuit Serial ProgrammingT (ICSPT) capability

a.. In-Circuit debugging support

a.. Programmable code protection
a..
--------------------------------------------------------------------

Please note that I don't have any electroninc knowledge... (but that
is hardly news i suppose
Why would I need 8 pins... what is so hard at getting a motor to
switch direction randomly



John Fields wrote:
For a toy, an 8 bit pseudo-random pattern is prob'ly good enough,
since you can get 255 tenth-second values out of the thing which you
load into an 8 bit down-counter, start the motor, and then count the
counter down with a 100ms clock. When the counter counts down to
zero, you send a clock to the pseudo-random sequence generator to
generate the next pattern, load it into the counter, reverse the
direction of the motor and run the counter down to zero again to start
the next timeout with the new value from the PRSG.


Would you be so kind and help me out a bit more.
Based on the info above I have a chip for less then 0,50 ct (still to much;
but ok... we're getting there)
Now how would you hook up a motor (what other parts are needed)...is there a
schematic example somewhere.
Where would I find motors (eg. lego/toy size...) I had hoped to keep this
whole
technical unit in the 1 to 2 dollar range...since it also need some plastic
parts too

Again; thanks for all the info you can give me.

---
I've already given you an algorithm which you can implement in the
simplest, least expensive ľC available and, since your application is
clearly commercial, I feel reticent to finish up the design and also
do your leg work without some form of compensation. If you're
interested in paying for further help, email me. If not, perhaps you
can find someone else to help you for free.

--
John Fields

 

[Bert]

John Fields wrote;

I've already given you an algorithm which you can implement in the
simplest, least expensive ľC available and, since your application is
clearly commercial, I feel reticent to finish up the design and also
do your leg work without some form of compensation. If you're
interested in paying for further help, email me. If not, perhaps you
can find someone else to help you for free.

Fair enhough... I wish it where allready commercial though

Regards,

Berrie

 

[petrus bitbyter]

"Bert" <b123s@hotmail.com> schreef in bericht
news:415be418$0$568$e4fe514c@news.xs4all.nl...

Thanks all for your help:

this is what I foud as the cheapest out there.
(don't have high volume price yet)
--------------------------------

Program Memory Type Standard Flash
Program Memory Size (bytes) 384
RAM Size (bytes) 16
Data EEPROM Size (bytes) 0
I/O pins 4
Packages SOT-23, 8p DIP

Features
a.. 6-pin SOT-23 packaging

a.. Precision 4 MHz internal oscillator

a.. Baseline Core with 33 Instructions, 2 Stack Levels

a.. All single-cycle Instructions except for program branches which
are two cycles

a.. 12-bit wide instructions

a.. 8-bit wide data path

a.. 25 mA source/sink current I/O

a.. Low power (100nA) sleep current

a.. One 8-bit timer (TMR0)

a.. Watchdog timer (WDT)

a.. In Circuit Serial ProgrammingT (ICSPT) capability

a.. In-Circuit debugging support

a.. Programmable code protection
a..
--------------------------------------------------------------------

Please note that I don't have any electroninc knowledge... (but that
is hardly news i suppose
Why would I need 8 pins... what is so hard at getting a motor to
switch direction randomly



John Fields wrote:
For a toy, an 8 bit pseudo-random pattern is prob'ly good enough,
since you can get 255 tenth-second values out of the thing which you
load into an 8 bit down-counter, start the motor, and then count the
counter down with a 100ms clock. When the counter counts down to
zero, you send a clock to the pseudo-random sequence generator to
generate the next pattern, load it into the counter, reverse the
direction of the motor and run the counter down to zero again to start
the next timeout with the new value from the PRSG.


Would you be so kind and help me out a bit more.
Based on the info above I have a chip for less then 0,50 ct (still to
much;
but ok... we're getting there)
Now how would you hook up a motor (what other parts are needed)...is there
a
schematic example somewhere.
Where would I find motors (eg. lego/toy size...) I had hoped to keep this
whole
technical unit in the 1 to 2 dollar range...since it also need some
plastic
parts too

Again; thanks for all the info you can give me.

Regards,

Berrie

Well,

Guess that six pin processor is the latest PIC. This one will do the job
equally good I think but there is still not much experience with it. The
25mA are good for a lot of things. Driving LEDs for instance. But a motor
that runs on 25mA at 5V? That 125mW power may be enough to move a clocks
arm but will hardly move any significant load. Common toys motors requires
some hundreds of milliamps, especially when just turned on, so you will need
a transistor to drive it. More then one transistor as you want to be able
to change the motors direction. The type of transistor mainly depends on the
motor you want to control and the type of motor depends on the load you want
to move. This things are not very difficult to find out but it takes time
and skills you obviously do not have yourself. People on this forum tend to
be very helpfull but I doubt you can find a volonteer to do the whole design
for you. Sooner or later you will need a pro. John Fields is one but I know
some in my own environment as well. For instance:

Wouter van Ooijen
http://www.voti.nl/

or

Sjaak van Schaik
http://www.jvanschaikconsultancy.nl/

petrus bitbyter


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.771 / Virus Database: 518 - Release Date: 28-9-2004

 

[Kenneth Lemieux]

I have a single chip 64x100 monochrome video generator in beta right
now. I expect it to be ready in a few weeks.

See www.speechchips.com for more information.

Thanks,
Ken


guitarpicker@ureach.com wrote in message news:<433ed59.0409201914.5aa3af9c@posting.google.com>...

Geo <hy1k-hwia@dea.spamcon.org> wrote in message news:<82grk01pimi8jr28pntv0u9dpd9hkud3mi@4ax.com>...
On 19 Sep 2004 09:55:55 -0700, guitarpicker@ureach.com wrote:

I posted this to some other newsgroups but I thought some of you might
be interested in this as well. I saw this product in the September
issue of Nuts & Volts. Its a video card for microcontrollers called
the ezVID from Multilabs. It uses serial lines for communications.
Seems like a good product for the price. It has decent resolution
with color video. The large SRAM based user character storage is a
nice addition to. I found it at www.multilabs.net and they also have
a decent applications page.

But no PAL just NTSC...

Geo

Geo,
Hopefully them will comeout with a PAL version soon.

Guitarpicker

 

[Bert]

Petrus bitbyter wrote;

Well,

Guess that six pin processor is the latest PIC. This one will do the job
equally good I think but there is still not much experience with it. The
25mA are good for a lot of things. Driving LEDs for instance. But a motor
that runs on 25mA at 5V? That 125mW power may be enough to move a clocks
arm but will hardly move any significant load. Common toys motors requires
some hundreds of milliamps, especially when just turned on, so you will
need
a transistor to drive it. More then one transistor as you want to be able
to change the motors direction. The type of transistor mainly depends on
the
motor you want to control and the type of motor depends on the load you
want
to move. This things are not very difficult to find out but it takes time
and skills you obviously do not have yourself. People on this forum tend
to
be very helpfull but I doubt you can find a volonteer to do the whole
design
for you. Sooner or later you will need a pro. John Fields is one but I
know
some in my own environment as well. For instance:

Yes... the point is very well taken ... don't mean to ride for free on
this one.
I'm just in the first stages of getting to know where and who to find.
So your reply is indeed very helpfull.

It does need to push something of a load... so you put me on an other track.
Although I'm not gettting all of it; I understand that there are more
electronic parts involved.
Which means "production costs" in some shape or form.

Although I'm "just the Toy guy" ....you know how it is; if it can't be
made for less
then a dollar... there's no bother calling "them" again
So that's what I'm doing; I'm trying to get a feel for how this
technical-bit would work out.

Thanks again.

Berrie

 

[larrymoencurly]

VWWall <vwall@DEADearthlink.net> wrote in message news:<FGk7d.563$M05.290@newsread3.news.pas.earthlink.net>...

Many modern drills are "double insulated", and hence don't require a
grounded body to be safe, so a two prong plug is OK.

I see many power tools with large areas of exposed metal on the
outside, yet they're still classified as "double insulated." How can
this be? For example, corded electric drills are often aluminum in
the front 2" of the body, circular saws almost always have a metal
blade guard, and in both situations this metal is in direct contact
with metal parts of the motor.

 

larrymoencurly said:

VWWall <vwall@DEADearthlink.net> wrote in message news:<FGk7d.563$M05.290@newsread3.news.pas.earthlink.net>...

Many modern drills are "double insulated", and hence don't require a
grounded body to be safe, so a two prong plug is OK.

I see many power tools with large areas of exposed metal on the
outside, yet they're still classified as "double insulated." How can
this be? For example, corded electric drills are often aluminum in
the front 2" of the body, circular saws almost always have a metal
blade guard, and in both situations this metal is in direct contact
with metal parts of the motor.

Double insulation refers to the fact that the armature has two levels
of insulation - the windings are insulated, and the bobbin that the
windings are on is insulated from the motor shaft with an epoxy insert
that provides an additional layer of insulation. Generally, the
brushes and wiring are also contained in a plastic housing. The metal
portion principally houses the reduction gears and bushings/bearings.

FWIW,

Greg G.

 

[Ron Reaugh]

<Greg G.> wrote in message
news:hhqsl0d6q5qnl9up5p6pm9k2mrovajj073@4ax.com...

larrymoencurly said:

VWWall <vwall@DEADearthlink.net> wrote in message
news:<FGk7d.563$M05.290@newsread3.news.pas.earthlink.net>...

Many modern drills are "double insulated", and hence don't require a
grounded body to be safe, so a two prong plug is OK.

I see many power tools with large areas of exposed metal on the
outside, yet they're still classified as "double insulated." How can
this be? For example, corded electric drills are often aluminum in
the front 2" of the body, circular saws almost always have a metal
blade guard, and in both situations this metal is in direct contact
with metal parts of the motor.

Double insulation refers to the fact that the armature has two levels
of insulation - the windings are insulated, and the bobbin that the
windings are on is insulated from the motor shaft with an epoxy insert
that provides an additional layer of insulation. Generally, the
brushes and wiring are also contained in a plastic housing. The metal
portion principally houses the reduction gears and bushings/bearings.

And of course it's all hermetically sealed such that when you drop it in
salt water no current escapes...I didn't think so. Use a third ground wire.

 

[David Maynard]

larrymoencurly wrote:

VWWall <vwall@DEADearthlink.net> wrote in message news:<FGk7d.563$M05.290@newsread3.news.pas.earthlink.net>...


Many modern drills are "double insulated", and hence don't require a
grounded body to be safe, so a two prong plug is OK.


I see many power tools with large areas of exposed metal on the
outside, yet they're still classified as "double insulated." How can
this be? For example, corded electric drills are often aluminum in
the front 2" of the body, circular saws almost always have a metal
blade guard, and in both situations this metal is in direct contact
with metal parts of the motor.

"Double insulated" doesn't mean there are no exposed metal parts (although
an all plastic outer shell might be one way to achieve it). It means there
are two, separate, layers of insulation between the live parts and anything
exposed to human contact. The theory being that if one fails the other
still provides isolation and, further, that the one likely to fail would
be, for example, the motor windings, rendering the tool unusable (I.E. a
second failure unlikely since why would you be trying to use a non working
tool?), with the armature insulating bobbin (second layer) still intact and
isolating the metal parts.

That doesn't mean the thing is utterly safe from abuse or something stupid
like dropping it in a filled bathtub or some nut shoving bent paper clips
into the vent holes. It simply means that it has double protective layers
to reduce the chance of shock when it's *properly handled*.

It is, of course, still better to have the third wire ground as well as the
'double insulation'.

 

[Kenneth Lemieux]

No chance at all (well just yet anyway). 640x480 is too high res for
this sort of video. The processor isn't fast enough and you need
plenty of ram. TV's aren't that hard to find.

"john jardine" <john@jjdesigns.fsnet.co.uk> wrote in message news:<cji4bg$6sa$1@news6.svr.pol.co.uk>...

"Kenneth Lemieux" <kenlem@maine.rr.com> wrote in message
news:74fa6435.0409301131.6b0e07fd@posting.google.com...
I have a single chip 64x100 monochrome video generator in beta right
now. I expect it to be ready in a few weeks.

See www.speechchips.com for more information.

Thanks,
Ken

Any chance of doing the same but for a VGA monitor? (ie standard 640X480).
It's usually much easier to find a PC screen than something that will
display video.
regards
jhon

 

[Frank Bemelman]

"Rich Grise" <null@example.net> schreef in bericht
news:7r58d.2425$r3.229@trnddc05...

On Sunday 03 October 2004 08:23 pm, Don Kelly did deign to grace us with
the
following:

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message
news:VHjgH3N5OGYBFwdi@jmwa.demon.co.uk...
I read in sci.electronics.design that Frank Bemelman
f.bemelmanx@xs4all
Or peanut butter jars. IP67 and cheaper

The lids go rusty.
----------
You haven't bought peanut butter for a while- nowadays both jar and lid
are plastic.-at least the one marked "kraft" in my pantry is made this
way
--

I think they haven't discovered plastic yet over there.

Some products have plastic lids and a few also plastic jars. I think
95% is glass and metal. Easier to recycle, glass is collected in large
glass containers and metal lids can be sorted from the garbage with
magnets.

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)

 

[John Woodgate]

I read in sci.electronics.design that Rich Grise <null@example.net>
wrote (in <n2a8d.4127$eq1.1143@trnddc08&gt about 'Water resistant motor',
on Mon, 4 Oct 2004:

I'm not the only
customer who would pay a premium price for honey in a package that
doesn't spill all over your shoes and stuff. As with mustard. And, for
that matter, ketchup.

We've had aimable (and fairly amiable) mustard and ketchup in Britain
for a long while now.

Hey! I think I've serendipitized a new axiom:

Guys like condiments that we can point.

'they', not 'we'. There are rules to this sort of stuff. That used to
include correct spelling; the creative people have often not been good
at spelling but their errors get through nowadays because no-one knows
any better.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Rich Webb]

On Tue, 05 Oct 2004 00:16:34 GMT, "Carl Gilbert"
<mr_carl_gilbert@hotmail.com> wrote:

Hi

I am looking to build a basic heating system using the attached design. It
incorporates a 555, a variable resistor, some diodes and other bits and
pieces I don't understand but soon will.

The only problem is finding/making a board for it. I made a board in school
once where we used some sort of pen to draw the outline and dipped the thing
in acid.

With cost as main the limitation here, what is the easiest way to achieve my
goal. Can I print my own board at a reasonable price (<Ł20-Ł30) for
resources or is there a service which I could use to get a board made for
me.

The only problem is, I would only want about 3 or 4 boards so I should
imagine most organisations would not be interested in such a small project.

For a one-off or so, you can just use perfboard/vectorboard. You could
use something like http://www.vectorelect.com/Product/Circbord/8019.htm
and cut the traces to isolate the nodes that belong together and then
solder in the components and wire the nodes together. Or just use the
kind with single copper rings around each hole and string the leads
together with wire & solder.

Doing a nice job with home etching is certainly possible -- lots of
folks do it -- but expect to make some investment in the equipment and
still end up with some boards having un-etched copper islands in places
and mossy, eaten-through traces in other spots.

However, take a look at http://www.olimex.com/pcb/index.html for one
place to get nice prototype boards done at a reasonable price. I'm sure
there are others (I'd like to hear about them, too) but the consensus
I've seen around here is quite positive with respect to Olimex. You'd
need to create the files for the board but there is a freeware not-for-
commercial-use license of Eagle that would work just fine for this
board. http://www.cadsoft.de/

--
Rich Webb Norfolk, VA

 

[Peter Fairbrother]

crossposting to 6 groups is too many! reply to sci.electronics.basics

please cc me on replies, I don't read seb. Thanks.

James Varga wrote:

Okay - I've got a simple project going on here and being a bit of a noob I
need some help

I've got three x 3mm blue LED's hanging off a QT110 (touch sensitive IC)

The QT110 consumes 20uA

Each LED consumes (i think) about 20mA.

Sounds about right.

How are you controlling the current? Internal resistance of the battery?
Then you may have a problem using NiMH cells, see below, as they have low
internal resistance.

I only have 5mm height to put this in so I'm stuck with a button cell
battery.

Problem. Can you go to 5.6 or 6.5 mm? That increases your options a lot. How
much width do you have?

The only other thing there is is a 10uF cap.

Don't you mean a 10 nF cap?

So help me out - how long would a battery of say 620mA last under constant
use?

If the led's aren't lit it will last a long time (years) if 620mA primary (=
non-rechargeable) cells are used - however, if you use NiMH cells they will
only last for perhaps six months, as they will self discharge.

When the led's are lit it will last 100 hours, if you get the current right.

The other thing I would think of asking is that is there an easy
way/schematic for charging a battery like this?

Exactly what kind of battery were you looking to use?

Blue led's take a higher voltage than ordinary led's, and will probably need
at least three cells (unless you use lithium primary cells) - some will need
four or even five! What led's are you using? It makes a difference, some
work at around 3 volts, some need over 5 volts.

Generally, button cells are not rechargeable, although there are some new
NiMH ones that are - but their voltage is lower, requiring more cells. They
are quite large though, and a 600ma cell is 6.5 mm high and about an inch
wide by an inch and a half long. They do not have primary replacements (you
can't take them out and put a non-rechargeable cell in, because you can't
get a non-rechargeable cell the same size).


Charging them can be done in several ways, the easiest is a low current
charger that will take half a day to charge and will not do too much damage
if left on a bit too long.

If people aren't going to want to think about whether to charge it or not,
and just leave it plugged in, there are several ways - first, a slow trickle
charge. Much the same as above but it will take a day to charge, and not
really recommended, although it will work and is simple and cheap. Better,
an hour per day charger on a timer, with a switch to charge for 12 hours
when needed.


Then you get into the area of battery state sensing chargers, which can take
you anywhere you can afford. How much is the finished item likely to be
worth? Are you going to be selling it?

How often will the leds be lit? How often do you want to charge it?




All that may be a bit too much theory, it is often better in such projects
to just try it and see what happens. You may blow up a few parts, buit they
aren't that expensive. Do try to measure the led current, and get it close
to 20 ma by adding cells or whatever.